Dietary Polyphenols and Non-Alcoholic Fatty Liver Disease

Abstract

Non-alcoholic fatty liver disease (NAFLD), which is emerging as a major public health issue worldwide, is characterized by a wide spectrum of liver disorders, ranging from simple fat accumulation in hepatocytes, also known as steatosis, to non-alcoholic steatohepatitis (NASH) and cirrhosis. At present, the pharmacological treatment of NAFLD is still debated and dietary strategies for the prevention and the treatment of this condition are strongly considered. Polyphenols are a group of plant-derived compounds whose anti-inflammatory and antioxidant properties are associated with a low prevalence of metabolic diseases, including obesity, hypertension, and insulin resistance. Since inflammation and oxidative stress are the main risk factors involved in the pathogenesis of NAFLD, recent studies suggest that the consumption of polyphenol-rich diets is involved in the prevention and treatment of NAFLD. However, few clinical trials are available on human subjects with NAFLD. Here, we reviewed the emerging existing evidence on the potential use of polyphenols to treat NAFLD. After introducing the physiopathology of NAFLD, we focused on the most investigated phenolic compounds in the setting of NAFLD and described their potential benefits, starting from basic science studies to animal models and human trials.

Olive Polyphenols: Antioxidant and Anti-Inflammatory Properties

“…An important feature of the MD is the daily consumption of a vast array of phytonutrients including vitamins and plant phenols, which provides its similarities with the Asian diet. In particular, plant polyphenols interfere with multiple signaling pathways involved in protein homeostasis, in the inflammatory response, and in the regulation of both metabolism and the antioxidant defenses [4][5][6], often recalling a caloric restriction (CR) regimen positively affecting, among others, whole body metabolism, mitochondrial turnover, oxidative stress and the inflammatory and neuroinflammatory response, where autophagy plays an important role [7,8]. Polyphenols can reach these effects by counteracting, at the molecular level, signaling pathways responsible for the cascade reactions involved in aging [9,10].…”

The Regulatory Effects of Citrus Peel Powder on Liver Metabolites and Gut Flora in Mice with Non-Alcoholic Fatty Liver Disease (NAFLD)

“…Tocmo et al [ 10 ] and Razola-Diaz et al [ 11 ] found that the phenolic compounds in pomelo peel and orange peel were mainly composed of mostly flavonoids and a small amount phenolic acids and that the biological activities exhibited by both peels, such as antioxidant, hypoglycemic, hypolipidemic, anti-inflammatory, and anticancer activities, were mainly attributed to their phenolic compounds content. Moreover, many researchers have demonstrated that a diet rich in polyphenols is effective in the prevention and treatment of NAFLD [ 12 , 13 ]. Bayram et al [ 14 ] suggested that polyphenols can improve NAFLD through different mechanisms, including antioxidant effects, anti-inflammatory effects, improved insulin sensitivity, prevented β-fatty acid oxidation, reduced de-novo lipogenesis, and improved adipokine.…”

Current Options and Future Directions for NAFLD and NASH Treatment

“…Polyphenols as anti-inflammatory and antioxidant reagents show a protective effect in liver disease, and consumption of polyphenol-rich diets also pride beneficial effects for NAFLD patients [ 131 ]. For example, a high intake of lignans, a large group of low molecular weight polyphenols in plants such as whole grains, reduces the incidence of NAFLD [ 132 ].…”